Talk:Fragmentation (computing): Difference between revisions

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==Slackcompaction==

I have just gone through the article and i was really wondering how would if i insert a setion

Slack is just a term used with internal fragmentation, and adds no new information to the concept. The article on slack will soft redirect here, so I am removing this article's link to slack. [[User:Qevlarr|Qevlarr]] ([[User talk:Qevlarr|talk]]) 12:11, 3 January 2008 (UTC)

about '''compaction''' (it removes external fragmentation by moving all allocated blocks to one end and free blocks to other) below the external fragmentation? <br />

I mean when you disscuss the issue of external fragmentation you should write about how it can be removed. [[User:Prashantgonarkar|Prashantgonarkar]] ([[User talk:Prashantgonarkar|talk]]) 03:39, 14 October 2011 (UTC)

== Double use of term "fragmentation" ==

== Terms Used ==

Fragmentation is a phenomenon where space is wasted, not the wasted space itself. Will see if I can get to fixing it. [[User:Qevlarr|Qevlarr]] ([[User talk:Qevlarr|talk]]) 12:15, 3 January 2008 (UTC)

:Opened some books, turns out both uses are pretty common. I will be adding something that says there are two uses: the phenomenon, and the wasted space itself. [[User:Qevlarr|Qevlarr]] ([[User talk:Qevlarr|talk]]) 12:55, 3 January 2008 (UTC)

I have just read through this article and was wondering whether file fragmentation is actually a "phenonemon" or is there a reasonable explanation for why it occurs?

[[Special:Contributions/83.104.81.241|83.104.81.241]] ([[User talk:83.104.81.241|talk]]) 16:28, 7 May 2009 (UTC)

:The 'Data fragmentation' section tries to explain it. See the [[File system fragmentation]] article if that was unclear. -- [[user:intgr|intgr]]&nbsp;<small>[[user talk:intgr|[talk]]]</small> 17:32, 7 May 2009 (UTC)

== Internal Fragmentation ==

I recently reverted an [http://en.wikipedia.org/w/index.php?title=Fragmentation_%28computer%29&diff=194595209&oldid=188526805 edit] that turned the Internal Fragmentation section into the text below. This text might have some useful contributions, but it's nowhere near good enough to replace the existing text yet.

{{quotation|

[[Allocation]] either including [[redundancy|reduntant]] information or data which are not going to be used.

The term "internal" means that the unusable storage is inside the allocated region but is not being used.

Purpose and advantages:

* Usually provides increased efficiency or simplicity.

Disadvantages:

* More difficult to reclaim than other forms of fragmentation.

** Usually the best way to remove it is with a design change. For example, in dynamic memory allocation, [[memory pool]]s drastically cut internal fragmentation by spreading the space overhead over a larger number of objects.

Examples:

* In many file systems, files always start at the beginning of a sector (simplifies organization, easier growth of files). Any space left over between the last byte of the file and the first byte of the next sector is a form of internal fragmentation called ''file slack'' or ''slack space''.

* Examples of use of metadata:

** Program allocates a single byte of data is often allocated many additional bytes for metadata and alignment.

* Examples of use of reserved (often unused) resources:

** [[IP address]]es can only be reserved in blocks of certain sizes (thus many IPs are reserved but not actively used). This is contributing to the [[IPv4 address shortage]].

** [[English language|English]] text is often stored with one [[Character (computing)|character]] in each 8-bit [[byte]]. Although in standard [[ASCII]] encoding the [[MSB|most significant bit]] of each byte is always zero.

}}

== External fragmentation a weakness of “certain” algorithms? ==

“It ''(external fragmentation)'' is a weakness of certain storage allocation algorithms, when they fail to order memory used by programs efficiently” – surely it is a weakness of all general purpose algorithms, and any that fails to adequately anticipate sequence of (de)allocation operations? If so, this should be changed – or am I missing something? [[User:PJTraill|PJTraill]] ([[User talk:PJTraill|talk]]) 10:35, 4 November 2017 (UTC)

: One approach to avoid external fragmentation is to move surviving objects such that they are stored contiguously in memory. This is possible only for programming languages where each pointer is well-defined and where all pointers can found. Then this could be done using a garbage collector that is free to move objects. Alternatively, you can work with allocations of fixed memory units where objects are not necessarily stored contiguously in memory (see [https://dl.acm.org/doi/pdf/10.1145/354880.354883]). This, however, requires compiler support. --[[User:AFBorchert|AFBorchert]] ([[User talk:AFBorchert|talk]]) 11:33, 17 December 2020 (UTC)

== 'File slack' and 'slack space' ==

[[File slack]] and [[slack space]] both redirect to [[Fragmentation (computing)#Internal fragmentation]], but these terms do not appear anywhere in the target article. – [[User:Tea2min|Tea2min]] ([[User talk:Tea2min|talk]]) 08:21, 9 July 2018 (UTC)

== DoubleFile usesystem of term "fragmentation" ==

I didn't want to attempt major surgery to this article, but there already is an article [[File system fragmentation]] that talks about problems with external storage. I would suggest that this article concentrate on main storage fragmentation and eliminate (or merge) the material on file system frag. [[User:Peter Flass|Peter Flass]] ([[User talk:Peter Flass|talk]]) 15:45, 15 July 2021 (UTC)

== India Education Program course assignment ==

[[File:Wikipedia-Ambassador-Program-Logo.png|50px]] This article was the subject of an educational assignment at College Of Engineering Pune supported by [[Wikipedia:Education program/Ambassadors|Wikipedia Ambassadors]] through the [[Wikipedia:India Education Program|India Education Program]]&#32;during the 2011 Q3 term.&#32;Further details are available [[Wikipedia:India Education Program/Courses/Fall 2011/Data Structures and Algorithms|on the course page]].[[Category:India Education Program student projects, 2011 Q3|{{PAGENAME}}]] [[Category:India Education Program student projects]]

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